The present invention pertains to fluid clutch devices; and more particularly to fluid couplings and torque converters, and a method for producing the same.
In a typical automobile having an automatic transmission, a fluid coupling or torque converter is used to transfer power from the engine to the transmission. A typical fluid coupling includes in its general organization an impeller 12 linked to the crankshaft 13 of the engine and a turbine 14 linked to the input shaft 15 of the transmission (See FIG. 1). The impeller 12 and turbine 14 are mounted face-to-face within a common housing that is filled with a fluid. Both the impeller and turbine include a series of vanes or blades that rotate about a central axis. When viewed along a plane perpendicular to the axis of rotation, as shown in FIG. 1, the impeller 12 and turbine 14 each resemble one half of a donut. As the engine operates, the crankshaft rotates the impeller, thereby causing the fluid contained in the housing to circulate. The moving fluid strikes the blades of the turbine, eventually causing it to rotate. The rotating turbine in turn imparts rotational movement to the input shaft of the transmission.
A torque converter differs from a fluid coupling in that it not only transfers, but also multiplies torque. In a typical fluid coupling, the circulating fluid returning from the turbine strikes the blades of the impeller at an angle that impedes its rotation. This reduces the efficiency of the coupling. A torque converter, on the other hand, includes a stator 16 rotatably positioned between the turbine 12 and impeller 14 to control the flow of returning fluid (See FIG. 2). The stator 16 includes a series of blades that redirect the fluid to strike the blades of the impeller at an angle that promotes rotation of the impeller. Accordingly, some of the energy of the moving fluid is returned to the impeller.
Fluid couplings and torque converters are typically produced through a complex manufacturing and assembling process. Generally, the impeller, turbine, and stator are produced by assembling a collection of independently manufactured blades on an appropriate support structure. The large number and complex profile of the blades makes this process both expensive and time consuming. As a result of the close proximity of the blades, fluid couplings and torque converters could not previously be manufactured through conventional die casting techniques.